Container sealing apparatus



Aug. 5, '1947. w. c.. JOHNSON 2,425,062

' CON TAINERISEALING APPARATUS Filed June- 26, 1945 8 Sheets-Sheet 1 jhuen or: warren Ck//JZJOIL M7%% g; i

1947. r w; c. JOHNSON CONTAINER SEALING KPPABATUS 8 Sheets-Sheet 3 Filed June 26, 194;

85 5, 1947. w. c. JOHNSON CONTAINER SEALING APPARATUS FiIed June 26 1945 8 She e ts--Sheet 4 Qfizveniizr: Warren G pfb/uwri 3 WW w. c. JOHNSON 2,425,062

CONTAINER S EALING APPARATUS I Filed .June. 26 1943 8 Sheets-Sheet 5 fizz/6711 07":

warren, uwon Aug. 5, 1947.

. W. C. JOHNSON CONTAINER SEALING APPARATUS Filed June 26, 1943- 8 Sheets-Sheet e fa, Ill

1947- w. c. JOHNSON 425,062

CONTAINER SEALING APPARATUS I 8 Sheets-Sheet 7 Filed June 26 '1945 fnvenfor; warren. LI /22507? I if A 7%?- Aug. 5, 1947. w. c. JOHNSON 2,425,062

' CONTAINER SEALING APPARATUS I Filed June 26, 1945 a Sheets-Sheet 8 fur/an er:

ZZ/ rren, C \finson Patented Aug. 5, 1947 CONTAINER SEALING APPARATUS Warren (3. Johnson, Cedar Rapids, Iowa, assignor,

by mesne assignments, to Quaker Oats Com- Application June 26, 1943, Serial No. 492,349

6 Claims.

This invention relates to apparatus for sealing containers and more particularly to continuous automatic machines especially adapted to receive paperboard cartons which have been filled with a desired product and to efiect closing and sealing of the top flaps thereof.

While a number of types of machines for this purpose, generally referred to as top-sealing machines, are available and many others have been proposed, they are generally not adapted to be used in connection with a packaging process involving heat-sealing of the top carton flaps, or they are characterized by relatively slow intermittent motion with attendant wear of the working parts. The machine of the present invention is so arranged that it is simple in construction, and fast and smooth in operation, and it is peculiarly adapted for heat-sealing the top flaps of fiiled cartons, although some of the novel features thereof are equally adapted to be used on sealing machines employing an ordinary adhesive to seal the cartons.

It is an object of the invention to provide a simple type of continuous top-sealing machine which is especially adapted to close and heat-seal the top flaps of cartons which have been coated with a thermoplastic material. Another object is to provide a top-sealing machine in which heat-sealing of the top closure is effected primarily by means of traveling belt means substantially synchronized with the motion of the cartons and through which heat is first transmitted to the top closure and then removed therefrom. Still another object is to provide an extremely simple arrangement for introducing cartons to be sealed into the carton pockets. Further objects,

advantages and uses of the invention will be apparent from the following detailed description of a presently preferred embodiment thereof, which should be read in conjunction with the drawings forming a part of this specification.

In the drawings:

Fig. 1 is a simplified view in elevation of one end of a sealing machine according to the invention showing the relationship of the carton supply and removal arrangements and various other features;

Fig. l--A is another simplified elevational view showing the other end of the machine of Fig, 1 and constituting a continuation of Fig. 1;

Fig. 2 shows in perspective the driving mechanisms which actuate the various devices incorporated in that end of the machine illustrated in Fig. 1;

Fig. 2--A is a continuation of Fig. 2 showing the driving mechanisms associated with the end of the machine illustrated in Fig. l-A;

Fig. 3 is a partial plan view of one of the duplicate carton-sealing lines with which the machine of Figs. 1 and 1-A is equipped, illustrating particularly the carton entrance arrangement, the operation of the carton pockets and the flap-folding devices;

Fig. 4 is an enlarged perspective view of the carton entrance mechanism in somewhat greater detail;

Fig. 5 is an enlarged perspective view of the first carton flap-folding mechanism;

Fig. 6 is an enlarged perspective view of the second of the flap-holding mechanisms;

Fig. 7 shows in perspective one of the carton pockets with its jaw members open for the reception of a carton;

Fig, 8 shows the carton pocket of Fig. '7 in closed position; 1

Fig. 9 is a fragmentary View showing the trip mechanism for synchronizing the entering cartons with the continuously moving carton pockets;

Fig. 10 is another view of the trip mechanism of Fig. 9 illustrating the position of the parts when the clutch member is engaged;

Figs. 11, 12 and 13 represent diagrammatically three successive stages in the folding of the end wall flap;

Figs. 14, 15 and 16 represent diagrammatically three successive stages in the folding of one of the side wall flaps; and

Figs. 17, 18 and 19 represent diagrammatically three successive stages in the folding of the overlying side wall flap.

The particular embodiment of the invention illustrated in the drawings is a top-sealing machine provided With two separate carton-sealing lines which are identical in construction and operation, but for the sake of brevity and simplicity, only one of these lines will be completely described. Furthermore, it will be observed that the drawings show little or no supporting structure such as frames, bearings, bearing supports, etc., since such structure is not essential to an understanding of the invention and could be supplied readily by one skilled in the art.

Referring first to Figs. 1 and 1-A, an endless chain 20 is arranged to travel over sprockets 2i and 22, so that its upper reach moves from left to right, and it is provided at regularly spaced intervals with a series of carton pockets generally designated at 23. While each of these arrangements will be described in detail below, Figs. 1 and 1--A indicate the relative positions of the carton inlet mechanism 24, the end wall flapfolding discs 25, the side wall folding devices 26 and 21, the endless belt 28 traveling over pulleys 29 and 30 and through which heat is transmitted to the carton tops from heating element 3!, the

endless belt 92 which travels on pulleys 33 and 34 and which is cooled by the cooling element 35, and the carton removal arrangement which comprises belt 36 traveling on pulley 31 and another pulley which is not shown.

It is believed that ltheloperation of ithese parts can be explained more simply if the driving mechanism which actuates them and which has been largely omitted from Figs. 1 and 1--A, is

to Figs. 2 and 2A. Due to the fact-thatall of the movements of the variousparts except .belt 36 must be synchronized, theyare BlLdriven from a single prime mover, which is illustrated by way of example in Fig. 2A as electric motor 40 and shafts 9! are also capable of rotating independently of one another.

Farther purposes of simplicity,theoperation of the carton-supplying mechanism will .be described as to the particular carton-sealing line 3 appearing closer to the observer in the various first described, and reference is, therefore, made which drives sprocket M through the speedreducing unit 52. Sprocket M in turn drives shaft 43 :by means of chain 44 and sprocket 45, thus causing uniform continuous motion of the chain 20 whichitravel on sprockets 22 rnountedon'shaft 43. At one end o f-shaft 43, sprocket 4,6 is provided which drives the two-coldbelts -32'by means of a linkage consisting'o-f chain '41; sprocket 4-8, shaft 49, gear '59, gear -5 I, shaft 52; sprockets -53, chains 54, sprockets 5'5 and shafts 56. The lower reach of each of the :belts '32 is located directly above one of *the chains and the gear and sprocket ratios are such that belts 32 travel ata linear velocity somewhat difierent from that of chains 20. Hot "belts 2-8 are similarly actuated from shaft 52 by means of sprocket 57,-chains 58, sprocket '59, shaft 60, sprockets 61, chains 62, sprockets t3, shafts 64 and pulleys 30, and they are substantially synchronized with-chainsizfl.

The remainder of the mechanism 'is actuated from shaft '65 CEig. ;2-) :upon which sprockets 21 are mounted and which is :driven by the movement of chains 20 over sprockets 2|. The flapfolding mechanisms 25, 26 and?! areall driven from v shaft which rotates ;at .a speed bearing a definite ratio .to that of shaft L65 since it is coupled thereto Eby :means ofsprocket .61, chain 68 :and sprocket :59. The rotation of end wall flap-folding discs 25 is accomplished by :means of chain rwrnnning over'sprockets CH, I2, (Band 14 and the relative sizes of thevarioussprockets involved are chosen in this case so that discs 25 make two complete revolutions during the time required for chain 12.0 to travel al -distance :egual to the spacing between equivalent parts-of adjacent carton pockets 2:3. The reason for this will .be discussed more fully when the ,-foldin g operation is described. The sidewall flap folders 26 .and .21 .are actuated by two vertical shafts l5 and '16 upon whichlaremounted the cooperating gears 17 and'JB, so that they turnat ane ual rate hut in opposite directions, .shaft '15 being in turn driven from shaft 166 by .means of the cooperating *bevel gears T9 and 88. It will :be understood that another pair of side wall jflap folders are similarly arranged and driven from the other end of shaft fifi.

The carton supply belts '8} which deliver the cartons to'the duplicate mechanisms fortransferring cartonsto the carton pockets ill'mounted on each of the chains 20 are synchronized'with thechains 20 and travel over pulleys 38 2- mounted on -shaft 83 and another pair of pulleys which are-:not shown. This'drive-runs from sprocket 85 on shaft55 through chain 85, sprockets B6 and 81 mounted on -sle eve 88, and chain 89, to sprocket :on shaft iis. Sleeve-88 isarranged to rotate on but independently of the shafts 9! and, since the latter are used to actuate the mechanisms for .pushingcartons into position tobe pickedup by the carton pockets 23 and it is not desirable to :have these mechanisms always operate simultaneously on both atop-sealing 'lines, the two drawings and it will be understood that like parts are provided to operate similarly in connection with the other such line.

Referring, therefore, 1to'2,.it willibe seen that shaft 92 is driven from sleeve 88 by means of sprocket 93, chain 94 and sprocket 95, and that shaft 92 in turn drives sprocket iii-by means of chain 95a and sprocket 35b. Sprocket 96 is arranged to rotate freely on shaft 9! and to actuate the adjacent portion Eil ofthe clutch 88 as is best illustrated in Fig. 4. The other portion 9.9 of the clutch 98 is keyed to shaft 9i and the clutch mechanism is so arranged that portion 39 will be actuated by the driven portion f9? only when trip arm 1-00 is released. "In this way, shaft BI and disc .HH driven therefrom hy'means of bevel gears 102 and 103, and shaft m l-rotat through one complete revolution every time trip arm {G0 is .released;

Since the object of the carton "entrance mechanismis to cause the cartons supplied to the machine-to be transferred individually without fail and-without'the possibility of jamming from belt 8i into the various carton pockets 23 asthey pass bi "0n continuous moving chain ElLit-is necessary that two conditions exist at 'the same time in order that the mechanism actuated by disc Ill! be :put into'operation. The first of these is that a carton should be ready to be pushed to aposition'jus't above chain 20 so-thatit can be picked up by an approaching pocket 23. This condition is assured by causing trip arm I50 to beheld unless there-are a pluralityandin this instance, at least five cartons awaiting further handling. This is best seen in Figs. 3 and lythe former of which shows the cartons on belt 8-! and between guides i'0-5 being held against further movement by rod 565 forming apart of the pushing mechanism. The last of these cartons bears against the roller l0! mounted on lever l'ilfi pivoted at I59 sothat rod Hll is moved to the left. From Figs. 4, 9 and 10, it will'be seen thatthis causes the lower end=0f lever Ill, which is pivoted at 2, to move away from and release trip arm 10!? since its lower end is provided witha hook portion H to which would normally engage tip arm Hi6. It is apparenutherefore, that as long as the supply of cartons is suificient, lever i 88, rod H0 and lever l H will be in the position shown in Fig. 10, and will not prevent the ngagement of the clutch 9B. When not enough cartons are available, this arrangement will prevent clutch 98 from becoming engaged and actuating the pushing device.

- The second condition, namely, that the approaching carton pocket 23 is in the proper spaced relation to the point of carton entrance, is achieved bysimilar-means. Referring again to Figs. 3-an;d-4, it will be seen that roller! l 3 mounted on lever H341 will engagethe upright post H4 forming apart of carton pocket 23 as it passes and that this will cause rod 1 it to be moved to the left. 'Thereupon, the lower end of lever H15, which also has a projectingportion [6a will be swung away "from trip arm let to the position shown in Fig. 10,-thus releasingtrip arm I00 and allowing the clutch 98 to become engaged and causing shaft 8i and disc H" to make a complete revolution as previously described.

Clutch 98 is of a conventional type but it will be described briefly in connection with Figs. 9 and 10. The ring portion 97, which is here shown swung away to reveal other portions of the device, is adapted to rotate on the laterally extending collar portion Me which is integral with portion 99, and it is, as previously mentioned, con nected to and driven by sprocket 96. Portion 99 is arranged to drive shaft III by means not shown and it is provided with a special key I I? which is circular in cross-section so that it may be rotated about its own axis in a cooperating keyway within member $9. Key II'I is rigidly affixed to trip arm Ifill which emerges from mem ber 99 through slot H8, so that key I I? will be rotated through a small angle as trip arm I90 moves between the positions shown in Figs. 9 and 10. Also trip arm I99 is normally urged in the position shown in Fig. by means of a suit-- able spring not shown. The other end of key I I1 consists of a flattened portion IE9 extending beyond member 99 and capable of being located entirely within suitable slot on collar portion 99a, and the parts are arranged so that this situation exists when the trip arm is held in its upward position as shown in Fig. 9.

It will be apparent that as long as trip arm I00 is held by either lever I I I or lever I I6, there will be no engagement between the key portion I I9 and the ring portion 91, and the shaft 9| will remain stationary. However, when both levers III and Mt are swung away from trip arm I09, and the latter assumes the position shown in Fig. 10 due to the urging of the spring previously mentioned, flattened portion H9 will partially emerge from its slot whenever it is in register with the groove I29 in the inner surface of the member 91. It is thus apparent that even though trip arm I IN! is released, the clutch will not be engaged until a very definite point in the cycle is reached, and that the shaft 9i will then be rotated until trip arm Iiiil is engaged by at least one of the levers I II and H6. Due to the fact that it is desirable to have the carton-pushing action relatively fast, the sprocket ratios chosen are such that one complete revolution is made in considerably shorter time than is required for chain 28 to move a distance equivalent to the distance between adjacent carton pockets 23. Consequently, trip arm Iilli will be engaged by lever H6 after each revolution, whereas it will not normally be engaged by lever III unless the carton supply is insufficient. Furthermore, it will be observed that all of the rotating mechanism is synchronized with the motion of the chain 20, and the location of groove I26 is such that the complete carton-pushing action can take place between the time the carton pocket post I I4 engages roller I I2 and the time that particular carton pocket 23 reaches the carton to be picked up by it.

The details of the mechanism for transferring the cartons successively and at the proper times with respect to the position of carton pockets 23 are best shown in Fig. 4. A pair of horizontal rods I2I extend on either side of shaft I04 just below disc Iiii and are supported at one end by bar I22, which in turn is supported by posts I23 mounted on a base member I24 secured to the machine frame not shown. The other ends of rods I25 are similarly supported on the other side of the machine and are similarly related to the shaft Hi l and disc Ill! associated with the cartonsealing line on that side of the machine as has already been stated. The working parts for both carton-sealing lines are identical so that only 6 one will be here described' A-block I25 is slidably mounted on rods IZI and carries depending therefrom a carton-pushing member I26, the latter having an offset portion I2! so that when the block I25 moves toward chain 28 and member I26 pushes a carton in that direction, the next carton on belt 8i will be retained in its position until member I25 has been returned to its original position, whereupon belt 8i carries this carton forward until it is retained by rods I86 which are also carried by member I26, This sliding motion is achieved by means of a curved rod I28 which is secured at one end to pivot I23 on the upper surface of block I25 and at the other to a pivot or bearing I36 on the upper surface of disc IiI near the circumference thereof. It will be appreciated, therefore, that whenever the clutch 88 is engaged in the manner already described, disc IfiI will make a complete revolution and member I26 will travel toward and away from the path of chain 2% so as to transfer a carton from belt SI to a point directly above the axis of chain 2? During this step, the carton slides upon plate ISI and rests partly on plate I3I and partly upon strip I32 which is separated therefrom by an opening I33 sufiiciently wide to allow the post H t of each carton pocket 23 to pass therethrough:

Referring now to Figs. 7 and 8, each of the carton pockets 23 consists of a base bar I3 3 extending across chain 29 and rigidly secured to one of the links thereof, as by welding, a pair of rigid rods I35 extending forwardly therefrom terminating in a cross bar I35 and the upright post I M mounted on bar I34 carrying the mechanism for receiving and gripping a carton near its upper edge. Rods I35 and cross bar I3 6 constitute the structure upon which the carton rests and bar I 36 has a pair of lugs I5? on its lower surface spaced apart so as to receive a portion of chain 29 between them. While lugs I3? are not secured to chain 29 they serve the purpose of preventing lateral movement of the forward portion of carton pocket 23 when chain 25 is traveling in a straight line and thus enhancing the stability of carton pocket 23 when folding operations are performed on the carton therein. Bar I36 is substantially longer than bar I341 so that it may enter the grooves its in guide I351 as shown in Figs. 3, 5 and 8. From Figs. 1 and 1A, it will be observed that guides I39 extend adjacent chain 26 throughout the entire upper reach of chain 29 between sprockets 2i and 22, and there is a similar pair of guides its extending alongthe' lower reach of chain 28 thereby preventing any sagging of the latter and keeping the carton pockets 23 moving always in a straight line.

Referring again to Figs. 7 and 8, the cartongripping mechanism comprises a cross bar IQI upon which are swingably mounted a pair of arms I42 having inwardly extending portions I43 at their ends. Arms It? together constitute a pair of jaws of such dimensions as to enclose the particular carton to be handled, and they, as well as bar MI, have secured to their inner surfaces a number of small plates Me extending above the upper surface of arms I42 to a point just below the top edges of the cartons to be enclosed thereby. Furthermore, these plates are of such thickness that when the jaws are closed as shown in Fig. 8, they will form a continuous collar which grips the carton firmly on all sides and holds it square, Furthermore, those plates I44 coming in contact with the carton side walls escapee,

are provided; with. portions I45 in: their: upper central section, which. project slightly inwardlyto =cause a sli htv inwardbending of thecarton wallssufiicient to prevent thefiaps on thecartcn endwalls from passingbelow the horizontalplane when they are folded. Also, it will be noted that members I4 I.', Mzand I43::constitute a shelf which is capable. of receiving such small amounts of excess. thermoplastic material as may be forced fromtheiflap. surfaces during the sealing operation to be described, so that this excess material does not remain on. the cartons and render them unsightly, nor does it. drip on the various parts oft-he, machine indiscriminately. Arms I42 are normally urged in the. openposition shown in Fig. 7 by means of coil spring I 46, but as soon as the pocket 23 has traveled past the carton entrance point, the arms are moved to closed position by the action of cams i4! acting on rollers I48. mounted on the. lower outer end of arms I 42. This is best illustrated in Figs. 3, 4 and. 8. As shown inFigs'. l and 1- -A, cam ele-- mentsv I41 extend along. the machine substantially. parallel to the path of chain 23, as the latter. passes around sprocket 22' and as it returnstoward sprocket up to a point near the latter. Consequently, each carton is firmly held in the carton pocket while the flap-holding, heatingand cooling operations are. being performed and then returns toward the entrance end of the machine in upside-down'position. Just before eachpocket passes upwardly around sprocket 2|, the. cams I41 flare. outwardly, thus, causing arms I42 toassumean open position so that the carton contained.v therein. slides. downwardly and rests upside down upon belt 38 for removal from the machine,

In order that the variousfeatures of the invention may be completely. understood, the operation of the embodiment thereof shown'i'n the drawings will be described with respect to? a typical carton passing through it, and thefdetails of such of these features ashave not already been mentioned. will be given in connection with this description. In this example, the cartons are conventional tubular cartons of rectangular cross-section, which have been bottom-sealed and filled. with the desired product, and which have a top flap on each. of the side walls coated with a thermoplastic composition, these flaps being adapted to be overlapped to form a top closure.

In starting up the machine, at least one and preferably several cartons are placed on belt 8! against rod I06. so as to assure the presence of a carton in the. proper positionto be transferred to anapproaching carton pocket whenever the trip mechanisms are displaced so as to release trip, arm I as shown in Fig. 3. Chain and consequently belt 8| are then started and, a' succession of such cartons. are made to approach the entrance mechanism on belt 8I between guides I 05,. Normally at least five cartons will be present or will accumulate on belt 8'I so. that roller I07 and lever I'IlB will be displaced in a clock-wise direction, and lever II I will be held away from trip arm I 110. As one of the carton pockets 23 approaches the entrance station, its upright column 4* will come in contact with roller IIE- and lever II3 will be displaced in a counter-clock-wise direction, thus causing lever II 6 torelease trip arm I90; As previously described; this actuates carton-pushing member I26 and the carton in contact with it is rapidly slid across plate I3I until it lies directly in the path of the approaching carton pocket. Pushing member I ZG'then returns to its original position and the next carton on belt M which has been; held back by the oil-set portion I21 movesforward suflicientlyto come in contactwith rod I05. In; the. meantime, carton pocket 23 continues its; motion and the carton in its path is picked up by it. Almost immediately rollers I 38 come in contact with cams I47 so that the arms I42 are swung to closed position and the carton is closely held. in upright position by the plates The carton thus held continues its travel until the, side wall flaps, that is, those which lie parallel to the direction of motion come in contact with guide rods I to. These rods are best shown in Fig. 5 and serve merely to displace the side wallflaps slightly outwardly for a short time so that the other pair of flaps, herein called end wall flaps, may be folded without possible interference from the sidewall flaps. The end wall flap-folding mechanism is very simple and consists merely in a pair of discs 25 which are mountedon shaft I5!) and rotated by means of sprocket 12 as previously described. Discs 25 are arranged so that at their lowest point their peripheries are substantially in the same plane as the top edges of the approaching carton andthey are spaced apart a distance such that they come in contact with the approaching end wall flaps near their side edges. Each of the discs 25 is provided with a cut-awayportion or notch I5I in register with each other and the motion of discs 25 and chain 26-are so synchronized that the notches IEiI face upwardly when discs 25 first come in contact with the leading end wall flap I52. Fig. 11 shows diagrammatically the relative positions of the carton and discs'25 shortly after the folding of flap I52.has begun, and it will be noted that this fiap is smoothly and easily folded by progressing beneath discs 25. As the movement of chain 20 and discs 25; continues, notch IiiI moves around and contacts the upper and outer edge of the trailing end wall flap I53, somewhat as shown in Fig. 12; so that finally flap IE3 is folded into the same plane as flap I52, as illustrated in Fig. 13. It is necessary, in order to achieve the result just described, that the circumferential speed of discs 25 be greater than the linear velocity of the carton and in this case the parts are so synchronized that discs 25 make two revolutions while chain 20 is moving a distance equal to that between the corresponding parts of adjacent carton pockets. In other words, notches I5I operate on a trailing carton flap during every other revolution of discs 25'. The advantages of this form of folding device are obvious since it is simple and smooth in operation and involves no reciprocating parts whatever.

Returning again to Fig. 5, a hold-down bar I5 3 is provided which retains flaps I52 and IE3 in their folded condition until the side wall flaps can be folded over upon them and this holddown bar I54 is heated by means of an electri cal heating unit I55 for the purpose or" preheating. the folded flaps and softening the thermoplasti material thereon, which removes any beadsor other irregularities in the material and materially aidsthe final heat-sealing operation. This pro-heating step is especially effective because of the fact that flaps I52 and I53 are prevented from entering the carton itself by the slight depression of the carton walls previously described so that they are necessarily held in good contact with the heated hold-down bar I 54 The carton in the advancing carton pocket is z'i-l then acted upon by the side wall flap-folding devices 2 3 and .2? which act successively to fold the side wall naps designated I58 and I59 in that order. cludes a member I56 which is arranged to present a straight edge use to flap I58 along a line just above the top score line of its associated side wall and so to fold 'flap E53 into contact with flaps I52 and I53, as illustrated diagrammatically in Figs. 14, and 15. This folding, however, is not done by moving the folding member I55 in a direction perpendicular to edge I63, but by causing it to follow a circular path such that edge I60 travels with, as well as toward and away from, the carton. This rotary motion is achieved by mounting the folding member I 55 upon a pair of rods I6I, which in turn are supported at one end by a block I62 mounted on an eccentric pivot on the upper surface of horizontal disc I63. Disc I63 is arranged to rotate about vertical shaft I64 and the other ends of rods It! are similarly mounted on a similar disc not shown, adapted to rotate upon shaft i5 (Fig. 2). Since shaft It,

as has already been shown, rotates in a counterclockwise direction, shaft use will do likewise and the folding member 555 will travel in a circular translational manner. Also, this motion is synchronized with the motion of chain 29 so that edge I511 is caused to approach and to move with I As shown in Fig. 6, flap folder 26 inported by block I 56 on disc I67, and the latter the parts shown in Fig. 6, folding device 26 is about to commence the folding of flap I58. These devices give efficient and positive folding action, due to the straight line action of the folding edges and they are also exceptionally smooth in operation because of the circular motion used; The folding members I55 and I5? are also provided with electrical heating units Ill and H2,

which serve to prevent the accumulation of thermoplastic material upon them and also to preheat flaps I58 and I59 so as to prevent cooling of the thermoplastic materials on flaps I52 and IE3 which have already been softened as described.

The carton in the advancing carton pocket is then ready for the heat-sealing operation, and so passes under the lower reach of belt 28, which holds the top flaps in their closed position. During the transition period these top flaps are kept closed by means of a series of rollers I13 which bear upon the uppermost of them. In the particular application of the invention being described, the top flaps are coated with a thermoplastic material and in order to heat-seal them, it is necessary to apply heat and pressure in a downward direction upon substantially the entire carton top so that this material may soften and flow so as to seal all of the cracks and crevices between and adjacent the flaps. It is; therefore, necessary that belt 28 should be heated in some way and in the present instance, belt 28' is of a material having a high heat conductivity through which heat passes from the electrical heating unit 3| to the top surface of the carton,

and the distance between pulleys 29 and 39 and the length of heating unit 3| is such that the desired amount of heat is transmitted to the carton tops. In the presently preferred form of the invention, belt 23 is an endless steel belt and it is slightly wider than the cartons being sealed so that the heat is transmitted as evenly as possible to the carton. Heating unit {ii is also slightly wider than the carton and it has a smooth lower surface upon which belt 23 slides easily and with little friction, even though that surface is adjusted vertically so that it exerts a definite and substantial pressure upon the cartons travelin thereunder.

Upon passing under pulley 30 and leaving belt 28, the carton moves forward until the top surface thereof comes in contact with belt 32; the top flaps in the meantime being held in closed position by means of rollers IM. While it would be possible to allow the cartons to cool while holding the top flaps closed by any suitable arrangement, this would result in an exceptionally and undesirably long top-sealing line, so that it is much preferred to cool the thermoplastic material at the top of the carton more quickly. In this instance, therefore, belt 32 is a steel belt similar to belt 28 and a cooling unit 35 is provided which has a smooth lower surface upon which belt 32 slides easily. Obviously the distance between pulleys, 33 and 34 depends to a great extent upon the nature of the cooling medium used and if a refrigerant is circulated directly within unit 35, this distance can be quite short. Another factor which must always be taken into account is, of course, the rate of travel of chain 20, since this would determine the time that each carton is being heated through belt 28 and cooled through belt 32. When the carton has passed pulley 34, it is completely cooled and the top closure is effectively sealed. The belt 32 has a wiping action on the carton top, due to the difference in speed between the belt andthe chain 20 by which the carton is carried, as explained hereinbefore. This action results in smoothing of the coating on the carton flaps and in eliminating or minimizing of breaks or gaps in the coating. More positive seal- M ing and better appearance are thus obtained.

Since cam tracks I41 extend around sprocket 22, the cartons remain in their carton pockets 23 and return substantially the entire length of the machine toward the entrance end but they are, of course, in upside down position. At a. point just short of sprocket 2|, cam tracks I47 flare outwardly so that arms I42 swing outwardly under the influence of spring I46 and the completely sealed carton is released therefrom. Belt 36 is arranged to travel somewhat below the cartons as they are released and slide downwardly from the various carton pockets in succession and serves to carry them in the same direction from the machine. Belt 36 and pulley 37 over which it travels, are not necessarily synchronized with chain 20, although they may be, but in this instance they are separately driven at a somewhat higher linear velocity so that the released cartons will be sure to clear pockets 23 before the latter start their upward travel around sprocket 2 I. One of the great advantages of this carton outlet arrangement is its simplicity, but another is the complete absence of reciprocating or timed motions which may get out of order.

It will be seen from the above that a carton sealing machine, in accordance with the invention, has been described which has many novel features and which is more advantageous th n the devices of the prior art for many purposes and especially for heat-sealing cartons whose closure flaps have been coated with a thermoplastic material. Obviously many modifications may be made by those skilled in the art in the light of the above disclosure, but such modifications are intended to be within the scope of the present invention.

While the invention has been described in connection with a specific embodiment thereof, it is not desired to be limited thereto, but only by the scope of the following claims.

I claim:

1. In a carton sealing machineincluding means for conveying a series of cartons in a predetermined path, means for subjecting the closure portions of said cartons to heat and pressure and means for subsequently cooling said closure portions while said cartons are moving in said path, the improvement wherein said cooling means comprises belt means adapted to exert pressure on said closure portions and means for driving said belt means in the same direction as said cartons and at a linear velocity approximating that of said cartons but sufficiently different therefrom to cause slippage between said belt means and said closure portions.

2. The improvement according to claim 1 wherein said belt means is composed of metallic material and is cooled by means of at least one cooling unit in contact with its surface opposite to that in contact with said closure portions.

3. In a carton sealing machineespecially-adapted for closing and top sealing a series of filled cartons having integral t'op flaps coated with a thermoplastic composition and adapted to be overlapped to'form top closures therefor, said machine including means for conveying said cartons continuously in a predetermined path, means for folding said top flaps to form carton closures, means for subjecting said flaps in closed position to heat and pressure sufiicient'to cause said composition to flow and to seal said cartons, the

improved cooling means which comprises belt means adapted to remain in contact with said closed flaps for a substantial period of time, means for cooling said belt means, and means for driving said belt means at a linear velocity approximating that of said cartons but sufiicient- 1y different therefrom to cause slippage between said belt means and the uppermost flap of "each of said cartons, whereby said belt mean has a wiping action on said uppermost flap and improves the continuity and appearance of the 'thermoplastic film thereon.

4. A carton sealing machine especially adapted for closing and top sealing a series of filled cartons having integral top flaps coated with a thermoplastic compositionand adapted to be overlapped to form top closurestherefor, comprising an endless chain conveyor, means for driving said conveyor continuously in a predetermined direction, a plurality of carton pocket means mounted on said conveyor at evenly spaced intervals, each of said pocket means'being adapted to receive a carton in upright position and to grip the same just below its top edges, means for folding-said top flaps to form carton closures as said cartons travel in said pocket means, means for subjecting said flaps in closed position to heat and pressure sufiicient to cause said composition to 110W and to seal said flaps, belt'mea'ns for holding said flaps in closed position while said thermo- "plastic material is being cooled, and means for driving said belt means at a linear velocity approximately equal to that of said conveyor but sufliciently different therefrom to cause slippage between said belt means and the uppermost flap onsaid conveyor at evenly spacedintervals, each of said pocket means having an open position in which it is adapted to receive a carton in upright position and a closed position in which it is adapted to grip the'same just below its top edges, means synchronized with said conveyor for transferring'a series of said cartons successively to a position directly into the path of said pocket means while said pocket means are in open position whereby said cartons are thereafter carried therein, means for causing said pocket meanssucc'essively to assume their closed position, means for folding said top flaps to form carton closures as said cartons travel'in said-pocket means, means for subjecting said'fiaps in closed position to heat and pressure sufficient to cause said composition to flow and to seal the interstices between said flaps, belt means for holding said flaps in closed position while said thermoplastic material is being co'ole'djand means for driving said belt means at a linear velocity approximately equal to that of said conveyor but sufliciently difierent therefrom to cause slippage between said belt means and the uppermost flap of each of said cartons, whereby said belt means has a wiping action on said uppermost flap and improves the continuity and appearance of the thermoplastic 'film thereon.

'6. A carton sealing machine according to claim 5 wherein said carton pocket means includes a pair of swingably mounted jaws having an open position whereby, a carton may pass between the leadingen'ds thereof, and means for urging said jaws to said open position, and means for closing said jaws after said cartons have entered said poclret means and for retaining said jaws in closed position until said pocket means have passed beyond said belt means.

WARREN o. JOHNSON.

REFERENCES crrsi) The following references are lot record in'the file'of this patent:

UNITED STATES PATENTS Number Name Date 733,460 Cormack Jul -:14, 1903 1,137,227 Martin Apr. 27,, 1915 1,4,v1,4s v Johnson Oct. 23, 1923 1,136,354 Martin Apr. 20,1915 1,198,7 10 Martin Sept. 19, 1916 1,423,094 Ferguson July 18, 1922 2,266,054 Lo'wey et al Dec. 1 1941 2,268,423 no e Dec. 30, 1941 2,195,159 Petskeyes Jan. 11, 1938 2,114,833 Fincke Apr. 19, 1938 

